Exhaust gas purifying system for an internal combustion engine

ABSTRACT

A single enclosure in which partition walls define two chambers and a by-pass passage interposed between the chambers. Each chamber contains an exhaust gas catalytic cleaning unit. A passage puts the outlet of the first chamber in communication with the inlet of the second chamber so that the exhaust gas enters the first chamber and issues from the second chamber. A single valve member is employed to either close the outlet of the by-pass passage and open the outlet passage of the second chamber or open the outlet of the by-pass passage and close the outlet passage of the second chamber.

United States Patent 1 Poullot et al.

EXHAUST GAS PURIFYING SYSTEM FOR AN INTERNAL COMBUSTION ENGINEInventors: Bernard Pou llot, Rueil; France Assignee:[authoritarianear,migrant;

and Regie Nationale Des Usines Renault, Billancou'rt, France Filed: June28', i971 App]. No.: 157,149

Foreign Application Priority Data July 16, 1970 France 70.26138 U.S. Cl.23/288 F, 60/296, 60/300,

' 60/30l, 55/DIG. 30, 423/2117 Int. Cl BOlj 9/04 Field of Search 23/288F,2 E; 55/DIG. 30; 7 60/301, 300, 296; 423/213.7

References Cited v UNITED STATES PATENTS 1/1967 -Eastwood 23/288 F [1113,7965% [45] Mar. '12, 1974 3,109,7l5 11/1963 Johnson et al. 23/288 F3,656,915 4/1972 Primary Examiner-1ames H. Tayman, Jr. Attorney, Agent,or Firm-Burns, Doane, Swecker &

Mathis [57 ABSTRACT A single enclosure in which partition walls definetwo chambers and ifby-pass passage interposed between the chambers. Eachchamber contains an exhaust gas catalytic cleaning unit. A passage putsthe outlet of the first chamber in communication with the inlet of thesecond chamber so that the exhaust gas enters the first chamber andissues from the second chamber. A single valve member is employed toeither close the outlet of the by-pass passageand open the outletpassage of the second chamber or. open the outlet of the by-pass passageand close the outlet passage of, the second'chamber.

2 Claims, 4 Drawing Figures Tourtellotte 23/288 F 1 EXHAUST GASPURIFYIN'G SYSTEM FOR AN INTERNAL COMBUSTION ENGINE The presentinvention relates to devices purifying systems for the exhaust gases ofinternal combustion engines provided with catalytic cleaning means.

A type of such purifying systems is known comprising a first purifierhaving a reducing agent, a second puri-- fier having an oxidizing agentmounted in seriesrelation with the first purifier, a bypass pipe, and amovable closing element whereby it is possible to allow the exhaustgases to pass through either the two purifiers or the bypass pipe. Thesesystems for reducing the pollution of the atmosphere are definitelyeffective, but unfortunately it is difficult to dispose them under thefloor of the vehicle owing to the size of the multiple connection tubes.

An object of the invention is to remedy this drawback by providing aparticularly compact unit.

Another object of the invention is to provide a system in which thecatalytic agents are easily accessible so that they can be rapidly andsimply replaced.

The invention provides a system "of theaforementioned type whichcomprises a' single enclosure defining two chambers in which thecleaners are disposed, said bypass pipe being disposed in the enclosure.between the two chambers and means being provided in the enclosure-forconnecting the outlet of the first chamber to the inlet of the secondchamber.

According to another feature, the reducing and oxidizing agents are inthe form of blocks secured to a plate constituting ade'tachable bottomwall of the enclosure. I

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawings.

In the drawings: 7

FIG. 1 is an exploded perspective view of a purifying system accordingto the invention;

FIG. 2 is a bottom view, with parts cut away, of the assembled system,and.

FIGS. 3 and 4 are sectional views on a reduced scale, taken along lines33 and 44 respectively of FIG. 2.

The drawings illustrate an exhaust gas purifying system for anautomobile vehicle adapted to be placed in the path of the exhaust gasesof the engine with which the vehicle is equipped.

It can be seen that the system is defined externally by a body 1 whichis closed on its lower face by a plate 2 held by fixing means such asbolts 3 and nuts 3" the body 1 and plate 2 constituting a case. Theinterior of the system is divided'by three partition walls 4, 5 and 6into two chambers 7 and 8 which are separatedby narrower compartments. 9and 10. Disposed in. the chamber 7 in a diagonal fashion is a basketcontaining a reducing catalyzing agent.v The unit therefore divides thechamber 7 into two parts 7 and 7". Similarly, another basket unit 12containing an oxidizing catalyzing agent is disposed diagonally in thechamber 8 and defines in the latter two parts 8" and 8. The units 11 and12 are secured to the plate 2 before it is assembled with the body 1.

The exhaust gases coming from the engine enter the compartment 9 by wayof one or two pipes 13, depending on the type of engine. The compartment9 and the upper part 7 of the chamber 7 communicate by way of anaperture 14 in the partition wall 4. A pipe 15 extending through thecompartment 9 connects the part 7 of the chamber 7 located under theunit 11 to the compartment 10 .which communicates by way of an aperture16 with the upper part 8" of the chamber 8. An aperture 17 located underthe unit 12 connects the lower part 8" of the chamber 8 to a passage 18which is formed at the end of the compartmentlO and separated from thelatter by a partition wall 19.

The passage 18 communicates by way of an aperture 20 with a chamber 21which is also connected by way of an aperture 22 to the end of thecompartment 9 remote from the pipe 13. An exhaust pipe proper 23 extendsfrom the chamber 21. A double valve 24 actuated in the known manner by alever 25 in response to a parameter, such as the temperature of thegases passing through the exhaust device, permits the closing of eitherof the apertures 20 and 22.

A pipe 26 permits the introduction into the compartment 10 of additionalair necessary for ensuring the oxidation reaction in the chamber 8. Thisair can be supplied by any known means and in particular by a turbinedriven by the engine.

The exhaust gas purifying system according to the invention operates inthe following manner:

lnnormal operation, the aperture 22 is closed by the double valve 24 andthe gases follow the path indicated by a full line. They pass first intothe chamber 7 where they pass through the cartridge 1 lof the catalyzerand then through the pipe 15 and the passage 10 and reach the chamber 8where they pass through the second cartridge 10. Thereafter, they escapeby way of the aperture 20. Thus it can be seen that the differentpollutants are either reduced in the chamber 7- or oxidized in thechamber'8, depending on their nature. The diagonal disposition of theunits enables a maximum thickness of catalyzer to be employed for agiven apparatus thickness.

If the temperature rises abnormally in the system to the extent of beingliable to deteriorate the catalytic products or even the apparatusitself, the double valve 24 swings over so as to close the aperture 20and open the aperture 22. The gases then follow the direct pathindicated in dot-dash line. The means for actuating this valve have notbeen shown and may be of any suitable type, for example the valve may becontrolled thermostatically. The system just described is particularlycompact and easy to insert in the exhaust-pipe placed under-the floor ofthe vehicle since it requires no connecting pipe or bypass pipe betweenseparate elements. Further, it is also easy to replace the catalyzingunits since it is sufficient for this purpose to dismantle the lowerplate 2 with no need to disengage the whole of the system.

I claim:

1. An exhaust gas purifying system for purifying the exhaust gases of aninternal combustion engine, comprisinga single case having an exhaustgas inlet and an outlet, gas-tight wall means defining two chambers inthe case which are substantially contained .in a common 1 substantiallyhorizontal plane, a first exhaust gas purifying unit comprising areducing catalyzing agent in one of the chambers, a second exhaustgaspurifying unit comprising an oxidizing catalyzing agent in the otherof the chambers,a first of the chambers having an inlet and an outletfor the exhaust gases and a second of the chambers having an inlet andan outlet for the exhaust gases, the inlet and outlet of each chamberbeing respectively adjacent said two opposite case ends, first passagemeans putting the first chamber inlet in communication with the caseinlet, second passage means putting the first chamber outlet incommunication with the second chamber inlet, third passage means puttingthe second chamber outlet in communication with the case outlet, aby-pass passageway interposed between the two chambers and having anoutlet and an inlet which communicates with the case inlet, and valve.

means consisting of a valve member combined with the by-pass passagewayoutlet and with the third passage means and movable between a positionin which the valve member simultaneously closes the bypass passagewayoutlet and opens the third passage means and a position in which thevalve member simultaneously opens the bypass passageway and closes thethird passage means, three partition walls within the case, two of thepartition walls defining with the case the two chambers and theremaining partition wall of said partition walls defining withsaid twopartition walls two intermediate compartments interposed between thechambers, a first of the compartments constituting the bypass passagewayand a second of the compartments constituting a part of the secondpassage means, a pipe extending across the first compartment and puttingthe first chamber outlet in communication with the second compartmentconstituting the rest of the second passage means, an air supply pipecommunicating between the exterior of said case and the first part ofthe second compartment the case being constructed in two main parts andcomprising a body carrying the chambers, the first, second and thirdpassage means and the valve member, and a detachable bottom wallcarrying the two exhaust gas purifying units.

2. A system as claimed in claim 1, wherein the exhaust gas purifyingunits are disposed obliquely in the chambers and thus define in eachchamber two taperber.

2. A system as claimed in claim 1, wherein the exhaust gas purifyingunits are disposed obliquely in the chambers and thus define in eachchamber two tapering spaces on opposite sides of the correspondingpurifying unit which tapering spaces have large ends respectivelyadjacent the inlet and the outlet of the chamber.